The article presents the concept of ensuring reliability during the operation of oil pipelines in an active tectonic fault zone. Possible solutions to this problem are considered. It is noted that at the present stage in the Russian regulatory and technical documentation, when calculating pipelines for seismic effects, a sharp displacement of the soil is not taken into account, leading to a violation of their design position. Using the example of the research object, changes in the stress-strain state of a pipeline with specified pipe wall thicknesses and plate displacement during an earthquake were considered. The minimum distances for the installation of shut-off valves in the area of the pipeline passing through a tectonic fault were determined. The total amount of economic and environmental damage from possible accidents on the oil pipeline under study has been determined, which allowed us to conclude that an integrated approach is needed to ensure the reliability of oil pipelines in the zone of an active tectonic fault.

Keywords: oil pipeline, active tectonic fault, reliability, stress-strain state, accident, shut-off valves, displacement of plates of the earth's crust

The design and construction of underwater pipeline crossings is a complex multifactorial task. Unfortunately, the existing recommendations on the design of these facilities, aimed at ensuring the reliability of structures, are not confirmed in operational practice. For example, with the trench method of building a single-pipe double-stranded structure, the distance recommended in the regulatory and technical documentation between the main and backup pipelines is often insufficient with intense deformation of the channel, which leads to a loss of bearing capacity of both strands of the underwater passage. Modern trenchless pipeline laying methods can minimize the risks of emergency situations. However, a number of factors, such as the pumping of corrosive products, the construction of oil and gas pipelines in difficult natural conditions (permafrost, increased seismic activity) require additional measures to ensure the reliability of underwater crossings. Our proposed option is to replace the single–pipe structure in trenchless pipeline laying with a two-pipe one. The objective of the study was to influence the fillers of the inter-tube space on the structural reliability of the pipeline and the feasibility of using the pipe-in-pipe construction method.

Keywords: underwater pipeline passage, pipe-in-pipe construction, trenchless technologies, inter-tube space filler